类固醇在母鸡卵泡壁生长调节中的年龄依赖性作用。
Age-dependent role of steroids in the regulation of growth of the hen follicular wall.
机构信息
Department of Functional Genomics and Bioregulation, Institute of Animal Genetics, FLI, Mariensee, 31535 Neustadt, Germany.
出版信息
Reprod Biol Endocrinol. 2010 Feb 15;8:15. doi: 10.1186/1477-7827-8-15.
BACKGROUND
The ovaries are the primary targets of senescence effects in mammalian and avian species. In the present study, relationships between reproductive aging, sex steroids and the growth pattern of the pre-ovulatory follicle wall were investigated using young hens with long clutch (YLC), old hens with long clutch (OLC), old hens with short clutch (OSC), and old hens with interrupted long clutch (OILC).
METHODS
Experiment 1: Hens were sacrificed 1.5 and 14.5 h after ovulation. Experiment 2: YLC and OILC hens were sacrificed 3.5 h after treatments with LH and/or aminoglutethimide (AG), an inhibitor of steroid synthesis. Volumes of pre-ovulatory follicles (F1-F5) and plasma concentrations of ovarian steroids were determined. Experiment 3: Granulosa and theca cells from F3 follicles of OSC and/or YLC hens were exposed in vitro to estradiol-17beta (E2), testosterone (T) and LH and the proliferative activity of the cells was examined using CellTiter 96 Aqueous One Solution Assay.
RESULTS
In YLC and OLC groups, the total volume of F1-F5 follicles rose between 1.5 and 14.5 h after ovulation (P < 0.01), negatively correlating with the plasma level of E2 (P < 0.01). There was no growth of pre-ovulatory follicles in the middle of the ovulatory cycle in the OSC group, with a positive correlation being present between E2 and the follicular volume (P < 0.05). In young hens, AG caused a rise in the total follicular volume. This rise was associated with a fall in E2 (r = -0.54, P < 0.05). E2 enhanced proliferation of granulosa cells from YLC and OSC groups. The proliferative activity of granulosa and theca cells of YLC hens depended on the interaction between T and LH (P < 0.01).
CONCLUSIONS
These data indicate for the first time that the growth pattern of pre-ovulatory follicles during the ovulatory cycle changes in the course of reproductive aging. E2 seems to play a dual role in this adjustment; it stimulates the growth of the follicular wall in reproductive aged hens, whereas it may inhibit this process in young birds. T and LH are apparently involved in the growth regulation during the pre-ovulatory surge in young hens.
背景
卵巢是哺乳动物和禽类生殖衰老效应的主要靶器官。本研究采用长产蛋间隔的青年母鸡（YLC）、长产蛋间隔的老年母鸡（OLC）、短产蛋间隔的老年母鸡（OSC）和长产蛋间隔中断的老年母鸡（OILC），探讨了生殖衰老、性激素与促排卵前卵泡壁生长模式之间的关系。
方法
实验 1：母鸡在排卵后 1.5 和 14.5 小时处死。实验 2：YLC 和 OILC 母鸡在注射 LH 和/或氨基导眠能（AG，一种合成类固醇抑制剂）后 3.5 小时处死。测定促排卵前卵泡（F1-F5）的体积和卵巢类固醇的血浆浓度。实验 3：OSC 和/或 YLC 母鸡 F3 卵泡的颗粒细胞和膜细胞在体外暴露于雌二醇-17β（E2）、睾酮（T）和 LH 下，用 CellTiter 96 Aqueous One Solution Assay 检测细胞的增殖活性。
结果
在 YLC 和 OLC 组中，F1-F5 卵泡的总体积在排卵后 1.5 和 14.5 小时之间增加（P < 0.01），与血浆 E2 水平呈负相关（P < 0.01）。OSC 组在排卵周期中期没有促排卵前卵泡生长，E2 与卵泡体积呈正相关（P < 0.05）。在青年母鸡中，AG 导致卵泡总体积增加。这种增加与 E2 下降有关（r = -0.54，P < 0.05）。E2 增强了 YLC 和 OSC 组颗粒细胞的增殖。YLC 母鸡颗粒细胞和膜细胞的增殖活性取决于 T 和 LH 的相互作用（P < 0.01）。
结论
这些数据首次表明，促排卵周期中促排卵前卵泡的生长模式在生殖衰老过程中发生变化。E2 似乎在这种调节中起双重作用；它刺激生殖老龄母鸡卵泡壁的生长，而在幼鸟中可能抑制这一过程。T 和 LH 显然参与了青年母鸡促排卵前激增的生长调节。
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